51�Թ�

The two-minute teaser video opens with a shot of a clapperboard before showing a montage of well-known locations from the show such as Hawkins High School.

Then a clapperboard claps, and the actor steps up to the mic.

A classic example is the view of the "cue card", or "clapperboard", that Apollo 8 astronaut Bill Anders used in his onboard "home movies".

But he neglected to use a clapperboard to sync up the visual footage with the audio, making it next to impossible to match the sound with screen imagery.

She added: “No directorial instructions were given, there was no clapperboard and no one was filming.”